1. Field of Invention
The present invention relates to electronic devices, particularly electro-optical devices, and to electronic apparatuses. More particularly, the invention relates to a pixel circuit of a voltage-follower-type current program system.
2. Description of Related Art
Displays using organic EL (Electronic Luminescence) elements are attracting people's attention. An organic EL element is one of current-driven elements of which the luminance is determined by the driving current flowing through the elements. One of the methods for writing data into pixels using organic EL elements is a current program system in which data is supplied to data lines based on a current. FIG. 10 is a known pixel circuit diagram of a voltage-follower-type (sometimes referred to as a “source-follower-type”) current program system. This pixel circuit is formed of an organic EL element OEL, a capacitor C, and four n-channel transistors. During the writing period in which data is written into the capacitor C by turning ON the switching transistors T1 and T2, the control transistor T4 is turned OFF to electrically separate the driving transistor T3 from a power supply voltage Vdd. The control transistor T4, which supplies the power supply voltage Vdd to one end (drain) of the driving transistor T3, is provided for each pixel circuit, and controls each pixel line extending along a scanning line.